As the worldwide demand for fossil fuels continues to increase, new, unconventional sources for fossil fuels must be developed because traditional sources are rapidly diminishing. One promising source is oil sand which is found in significant quantities in several parts of the world, most notably Canada and the state of Utah and most of the United States oil sands reserves are in the state of Utah. Oil sands contain naturally occurring mixtures of sand, clay, water, and bitumen. Because of this composition, oil sands cannot be extracted in the same manner as oil in an oil field. Instead, if the oil sands are not accessible using traditional mining methods, the oil sands are either mined and processed for the oil extraction or oil is extracted without mining using specialized techniques. In the event, a particular specialized technique will be chosen based on the composition of the oil sand being extracted and the depth and saturation of the oil sands deposit. Stated differently, every oil sand deposit cannot be extracted using a single, common method.
An important consideration when attempting to extract oil sands is the wettability of the rock or sand where an oil sand deposit is situated. There are basically two types of wettability that are encountered when dealing with oil sands. They are water wet and oil wet. In the water wet condition, a thin film of water coats the surface of the bitumen contained within the oil sand. Various techniques have been effective with water wet oil sands for extracting bitumen. One such effective technique is a conventional hot water process where the hot water washes bitumen from the oil sand and replaces it with water. Techniques for recovering bitumen from oil wet oil sands, however, have been more problematic.
In the oil wet condition, the material surrounding the bitumen is in direct contact with bitumen. This condition is much more difficult from an extraction standpoint because the traditional hot water process is not as effective. On this point, various extraction methods for oil wet oil sands have been attempted using heat, ultrasonic waves, and microwaves, but none have been commercially successful. In addition, various types of solvents have also not been successful for this purpose. Furthermore, no commercially viable method has been developed that can extract bitumen equally well from either water wet or from oil wet oil sands.
In light of the above, it is an object of the present invention to extract bitumen from oil sands in a commercially viable manner. Another object of the present invention is to develop a liquid solvent that, along with an additive, can be used to effectively extract bitumen from both water wet and oil wet oil sands. Still another object of the present invention is to use a solvent to create a fluidized bed that can facilitate the separation of bitumen from oil sand. It is another object of the present invention to provide an oil sand extraction system and method that are relatively easy to implement, cost effective and simple to use.